Re: [Xen-devel] [PATCH] x86/PoD: fix (un)locking after 24772:28edc2b31a9b

["Andres Lagar-Cavilla" <andres@xxxxxxxxxxxxxxxx>]

>>>> On 13.08.12 at 14:11, "Jan Beulich" <JBeulich@xxxxxxxx> wrote:
>> That c/s introduced a double unlock on the out-of-memory error path of
>> p2m_pod_demand_populate().
>
> I also wonder how correct that changeset's elimination of the page
> alloc lock in a number of places here is - p2m_pod_set_mem_target()'s
> calculations, for example, involve d->tot_pages, which with that lock
> not held can change under its feet.

afaict, access to d->tot_pages was not protected by the page_alloc lock
even prior to 24772.

Back when, I thought those unprotected tot_pages accesses should either be
locked or atomic_read(). Slipped through the cracks.

Andres

>
> Jan
>
>



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